1. Field of the Invention
A tissue culture dish is disclosed the is designed for easy manipulation of cells, specifically intracytoplasmic sperm injection.
2. Brief Description of the Prior Art
Formation and growth of mammalian embryos has become increasing important. The advances in understanding of the mechanisms of ovum generation coupled with advances in ultrasound imaging and micro surgical techniques have fostered a tremendous increase in formation and growth of mammalian embryos, both for domestic animals and especially for human embryos as in vitro fertilization (IVF) techniques have been perfected.
In a human IVF procedure generally the female is treated with hormones to stimulate maturation of multiple ova. These ova are then surgically recovered by micro surgical techniques directly from the ovary. The recovered ova are then placed into a suitable vessel and exposed to sperm collected from the male for fertilization. After fertilization occurs, the fertilized ovum is allowed to grow to a multicelled embryo, then recovered and returned to the female, where implantation of the embryo on the wall of the uterus is expected to occur, resulting, from that time forward, in a normal pregnancy.
In order to generate a suitable embryo for implantation by the IVF procedure briefly outlined above, practitioners must be highly skilled in many manipulative procedures as well as interpretation of laboratory results. Initially, a determination needs to be made of the dosage of hormones to be administered to the female. This determination may involve specialized blood tests, ultrasound imaging and laparoscopic procedures. During the hormone dosage phase, blood hormone levels are determined and ultrasound evaluation of the ovaries is often practiced. The collection of the ova is another specialized procedure involving ultrasound imaging and microsurgery. Once the ova are collected, careful microscale manipulations and optical microscopic evaluation of individual ovum, sperm, fertilized ovum and embryo are part of the process to generate an embryo suitable for ultrasound imaging and micro surgical techniques. In each phase, specialized equipment plays an important role in the success of the procedure.
Specialized equipment has been developed to assist practitioners in every phase of the IVF process. An important part of the process is the phase where the collected ova are placed into a laboratory vessel for the fertilization and growth. Initially, practitioners used ordinary glass petri dishes (hence the "in vitro" [glass] terminology). Specialized laboratory ware such as that disclosed in international Patent Application No. WO 91/06624 by Lyman et al. is available. Lyman et al. teaches a dish for IVF procedures. The dish has a single fertilization well concentrically surrounded by a second well for containing a humidification fluid. The humidification well with the fluid helps to maintain humidity in the fertilization well when the lid, similar to an ordinary petri dish lid, is in place on the dish.
European Publication No. 0 239 450 by Cassou teaches a carousel apparatus for IVF. The Cassou apparatus is complex, holding many dishes and including a glove box for facilitating the handling of the dishes and a microscope for observing the contents of the dishes during manipulation.
There are also multiwell dishes intended for tissue culture. U.S. Pat. No. 3,883,398 to Ono teaches a multiwell microculture slide chamber for simultaneous growing of a plurality of monolayer cell cultures on a slide which can then be separated for microscopic study of the culture.
U.S. Pat. No. 5,484,731 to Stevens discloses a Multiwell In-Vitro Fertilization Plate for receiving ova, forming, evaluating, holding, manipulating and culturing embryos. The well containing body of the device is provided with lids which close over the wells and allow for incubation.
The use of the wells, some of which are relatively deep, restrict operator and/or equipment movement.
The disclosed procedure dish eliminates the prior art problems by providing an easy device for moving and manipulating cells.